ELECTRIC POWER IN PERIL? Modern power grids are increasingly vulnerable to strong solar storms. A new NASA project named "Solar Shield," however, could help keep the lights on. Get the full story from Science@NASA.

BIG SUNSPOT: Sunspot group 1117 continues to grow, more than doubling in area during the past 48 hours: movie. Each of the primary dark cores in this Oct. 26th snapshot from the Solar Dynamics Observatory is fully as wide as Earth:

The sunspot's magnetic field is crackling with B- and C-class solar flares: 36-hour movie. So far, these impulsive eruptions have not hurled any substantial clouds toward Earth. A big flare would be geoeffective, however, because the sunspot is almost-squarely facing Earth. Stay tuned!

ARCTIC AURORA OUTBURST: On Oct. 24th, an outburst of color bright enough to rival the Moon spread across the skies of Scandinavia. Thilo Bubek sends this picture from the outskirts of Tromsø, Norway:

"The auroras were beautiful," says Bubek. Bright moonlight often overwhelms auroras, but in this case the nearly-full Moon was an asset. "It illuminated the landscape, setting the stage for a nice photo-op."

The source of the display was a high-speed solar wind stream, which hit Earth's magnetic field over the weekend, sparking two days of intermittent polar geomagnetic activity. It could turn into three days: High-latitude sky watchers should be alert for more auroras tonight as the solar wind continues to blow.

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.